textproduct: Quad Cities

KEY MESSAGES

- Windy conditions into this morning with peak gusts between 45-55 mph. A period of light snow and even some heavier snow showers may accompany the strong winds leading to reductions in visibility.

- Additional clipper systems will likely result in periods of accumulating snow Thursday through Sunday.

- Temperatures will drop for the weekend with wind chills well below zero Friday and Saturday night.

SHORT TERM /THROUGH THURSDAY/

Issued at 301 AM CST Wed Dec 10 2025

Early this morning an impressive 15 hPa MSLP gradient existed across the state of Iowa. MSLP 3hr pressure falls are 6 to 7 hPa ahead of the 990 hPa surface low quickly moving northeast of the area today. This intense gradient is leading to westerly winds gusting 40 to 50 mph across the area. As far as 50 kt gusts have gone, they have currently been limited to far NW IA and just ahead or behind the cold front. This means that some of our better wind gusts will likely occur between 11z and 14z, before starting to slacken.

Also, upstream no blowing snow has been reported. This is likely due to the temperatures being above freezing, leading to snow melting on top and acting as a better cap on any blowable snow underneath. Will continue to monitor upstream and will message with graphicasts if we start to see blowing snow.

Showers on the back side of the low are wrapping down into the area this morning. As noted by other shifts, we have ingredients in place for strong snow showers/snow squalls. Instability exists in most soundings, coincident with the arrival of the cold air. CAMs don't really have a signal for potential showers. Also, looking at the soundings when we do have instability it appears that we may not have ice nucleation, so if squalls were to develop, I wonder if they would mostly be graupel instead of snow. Nonetheless, ingredients remain in place this morning for snow squalls with strong winds and if they were to occur we could see significant reduction in visibilities and rapid accumulation. While temps do drop, I'm not sure we drop fast enough to see a flash freeze coincident with potential squalls. I am more concerned about the melt washing road treatment off area roads so that when the cold air arrives, we actually end up with icy roads. So be cognizant of that potential, especially later in the morning.

Snow showers are still possible today on the backside of the low in the cyclonic flow. CAMs have some signals but aren't that robust. With winds weakening, any of these showers that form may drop some light snow accumulations at best.

LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/

Issued at 301 AM CST Wed Dec 10 2025

Overall changes in the long term forecast were minimal. Do think we will need an advisory for accumulating snow Thursday night into Friday morning where 3 to 5 inches are possible across the CWA. Some guidance has a better signal for a wintry mix across our southern CWA, so that could be an issue as well and will likely warrant an advisory as well. With current products out, decided not to issue anything new on this shift but will use packets and social media to message the next two clippers.

For a more robust technical discussion of the two clipper setups, please refer to the discussion below from the earlier shift!

First, let's discuss the clippers. The first is progged to come through Thursday night, driven by 850-700 mb layer warm air advection/frontogenetic forcing. Precipitation types appear to be largely snow in our CWA, although there is a noticeable warm nose aloft around the 700-800 mb layer in the NAM/GFS soundings over our southern counties, which could support a wintry mix. Where snow is expected, this clipper could bring a few inches of new snow accumulation, given NBM probabilities of two inches of snow or greater is around 40-60%, particularly over northwestern Illinois into northeastern Iowa. The character of the snow appears to be more of a slightly drier snow to the northeast (snow ratios of 13-15:1) compared to farther southwest, where a wetter snow is more likely (snow ratios 7-10:1). Precipitation should be mostly over by sunrise Friday morning, with high pressure gradually nosing into the region through the day. A much colder air mass is expected to move into the region Friday night, right before the second clipper moves across the area Saturday. Friday night low temperatures look to fall to the single digits above zero for most locations. Due to the colder air mass in place, p-types are expected to be entirely snow, and pretty dry and fluffy snow at that. LREF ensemble mean soundings shows a deep thermal profile (from the surface up to around 700 to 600 mb) firmly within the DGZ, which supports a dry, fluffy snow character. Snow ratios of 15-19:1 are very much on the table, but with a weak signal for snow, it appears that blowing snow isn't going to be much of an issue. The second clipper appears to have a weaker signal for snow accumulations compared to the first, with NBM probs of two inches only around 30-50%.

In the wake of the second clipper system, an arctic air mass builds in for Saturday night into Sunday morning. Both the GEFS and ECMWF ensembles for 850 mb temperatures suggest magnitudes around 12 to 16 degrees C below zero, which would be some of the coldest air yet this season. These 850 temperatures would be near the daily minimum for December 14th at 12z (6 AM) per SPC sounding climatology, so a very cold air mass for this time of the year. Northwest winds look to stay elevated enough to combine with negative single digit and lower teens low temperatures to support widespread wind chill values of -15 to -30 degrees for most of the CWA Sunday morning. LREF exceedance probabilities of wind chills 20 degrees below zero or colder is around 50-80% for locations along and north of Interstate 80, so a pretty strong signal for a bitterly cold morning. Cold weather headlines are likely needed, if these trends continue. After Sunday, temperatures look to gradually warm as southerly return flow around the departing high should moderate temperatures into the early portions of next week.

AVIATION /12Z TAFS THROUGH 12Z THURSDAY/

Issued at 447 AM CST Wed Dec 10 2025

Have seen quite a few 50 knot gusts across central Iowa this morning, current wind forecast looks on track so have not backed off the forecasts. This should peak by 13Z. Airports without E/W runway configs will likely see crosswinds that may limit aircraft operations. Winds will gradually diminish through the day and gusts should drop off after 00z Thu. Could see some snow showers this AM that could drop vsbys with snow and gusty winds, temps currently cover that threat but may need to be adjusted as cold front approaches.

DVN WATCHES/WARNINGS/ADVISORIES

IA...Winter Weather Advisory until 9 AM CST this morning for IAZ040>042-051>054. Wind Advisory until 9 AM CST this morning for IAZ063>068- 076>078-087>089-098-099. IL...Winter Weather Advisory until 9 AM CST this morning for ILZ001- 002-007. Wind Advisory until 9 AM CST this morning for ILZ009-015>018- 024>026-034-035. MO...Wind Advisory until 9 AM CST this morning for MOZ009-010.